www.iFourWinns.com

It also makes you wonder what led to the need for a new engine (although the boat is 15 years old). Marine engines can last a long time, the things that do them in are being under propped (yours clearly is not because it reaches more than peak RPM), over heated, or killed by bad exhaust that lets water back in the engine (leaky manifolds, risers or gaskets).

I have taken out a few impellers used for 2-3 seasons and what seems to happen is that they take a 'set' with the vanes a certain way, now all of them still touched the inner liner of the pump, but it is possible that used ones do not pump as efficiently as a new one would. I have 2 laying in the boat out of the liner to see if they go back to the original shape or not. I have read on a another site that some mechanics recommend taking them out over the winter storage season and letting them sit so that they do not take a set. Not sure if it makes a difference or not. This is easy on a Volvo or a Cobra but not so easy on an Alpha or outboard (pump in lower unit).

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Well DHL delivered the parts, tonight im going to fit them and test drive te boat. I will give an update.

The good news is.. the raw waterpump pumps like a dream with the new impeller.
The annoying news is.. now that the raw waterpump pumps like a dream the engine runs cold all the time which would indicate a tstat stuck open or the tstat bypass channel blocked by debris.
Next im going to take out the tstat, check the channels of the tstatt housing for blockage and refit a new tstatt. The problem should be solved then. (i hope).

The engine starts perfect en idles en revs up very smooth. When this cooling issue is solved i think its a nice engine.

I am betting that you will find the thermostat is not there (removed), although stuck open is possible.

If they were short-cutting items like the waterpump and thermostat when they put a new? engine in, then maybe you need to check some other items:
Make sure drive oil has been changed
Check engine/drive alignment
Check hoses and belts for age/condition
Check fuel lines & change fuel filter
If Carbureted, clean fuel screen at carburetor.
Visually check Distributor Cap and Rotor Condition (and Points if applicable)
(and any other annual maintenance items)

_________________

"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings

the tstat is there, i removed the tstat housing.

You are right about the common maintenance items. I dont believe they were shortcutting because everything was in there and the whole engine bay and engine looked clean and cared fore. I checked the hoses and they are flexible and good. Also the risers manifolds are good (not new but not clogged). Belts look new. As far as visible the enginegaskets are all new also.

My take on this is that the previous owner was not intentionally withholding maintenance information but was not totally honest with me in saying the new base block was fitted last year pre season. The reason i think that is due to the fact that the impeller looked new but the compressed vanes lost their flex which suggests that the boat has not been driven for a longer period than 1 winter.

In hinnsight i should have asked more questions before closing the deal but on the other hand this is my first inboard and when this is fixed i learned:

- where to look at in the future with other boats regarding inboard systems
- how a VP engine is putt together
- how to do the basic maintenence myself on the VP

I think i found the reason the engine wouldnt heat up. There was a large piece of old impeller that was forced into the bypass channel preventing the passing of the water coming from the raw waterpump.
The mounting pressure in the cooling system pushed the thermostat open preventing the engine to warm up. I tested the old thermostat in hot water and it works as it should. I read about a few people with the same problem and they all had a blocked bypass in the thermostat housing.

Tomorrow i get the new thermostat. Saturday im going to test the boat.

Great work, mate!
Now, some pictures of your boat?!

_________________
2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

Thanks, well i tried to post the pictures with the img button but that didnt work. I will try again tonight after work.

Great job. Good luck with the Sea Trial.

There is a whole thread about posting pictures, but here is the short version:
1. The pictures must be hosted elsewhere (many free websites to choose from, such as snapfish.com)
2. The picture must be no larger than 1024 pixels wide x 768 pixels high
3. The link to the picture must be between the img /img markers

_________________

"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings

Well i test drove my boat today with the new tstat, impeller and cleaned tstat housing.

The temp on the gauge went up again to 220 and dropped when the engine was revved up above 2500rpm. I didnt trust the gauge because nothing was indicating the engine was overheating so we took the IR gun out. Below the results:

Lakewater temp: 46F/8C

1000RPM in gear:

Temp gauge indication: 220F/104C
IRgun at temp sensor: 151F/66C
IRgun at cilinderhead: 151F/66C
IRgun at tstat housing: 151F/66C
IRgun exhaust manifold: 92F/30C
IRgun Riser: 77F/25C

2500RPM in gear:

Temp gauge indication: 190F/88C
IRgun at temp sensor: 120F/49C
IRgun at cilinderhead: 127F/53C
IRgun at tstat housing: 122F/50C
IRgun exhaust manifold: 93F/34C
IRgun Riser: 81F/27C


WOT in gear:

Temp gauge indication: 130F/54C
IRgun at temp sensor: 104F/40C
IRgun at cilinderhead: 104F/40C
IRgun at tstat housing: 104F/40C
IRgun exhaust manifold: NA
IRgun Riser: NA

Conclusion: Temp gauge, sensor or cables are crap and worthless. Enginetemp at idle good and steady which points to the tstat working properly. Engine temp drops when RPMs increase which points to a tstat stuck open?

This conclusion seems contradictory. Im i missing something? Do you guys have any suggestions?

Believe it or my old 88 has pretty accurate gauges. What I have found is if you measure the area right under the t stat housing (part of the intake manifold) it is very close to the dash gauge (manifold=155-160, dash gauge 160-165) this is with a known good thermostat. If I check the top of the Thermo housing it reads lower like yours. Try checking the part of the manifold right under the Thermo housing.

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Hi louc

Thank you for the tip but im not sure what extra info measuring on yet another point would give me. I checked the hole engine with the gun and i chose a set of spots to measure with different Rpm. I think the readings are a pretty accurate and indicate good temps at idle (especially considering the low lake water temp.) and a drop of aprox. 70degrees between idle and WOT.

Does anyone has a theory on why the temp fluctuates this much and especially on why it decreases the higher the RPMs assuming the tstat works as it should?

Well it could be a flake of rust keeping the stat from closing when it needs to, I have had this problem on and off over the years. But why would it be more noticeable at high speeds is the question. I usually had the reverse issue, it would run too cool at idle with a stat that wouldn't close and come up to normal temp on plane.

the reason I said to measure it there, is that you will get different readings depending on where you shoot the t stat housing. The only spot that correlates consistently with the temp gauge is right under the housing on the manifold. All other parts of the housing are a good bit cooler. The top is usually like 100-105 or so, but thats because its getting cooled by the cool water the impeller is pumping in. I can tell when the stat opens because not only does that area under the housing start to get hot, but the big hose from the t stat housing to the water pump gets hot too because the t stat is letting hot water flow out of the engine.

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Those are baffling numbers.

I can only suggest replacing the thermostat, as they don't cost much anyway. Perhaps it is failing in a way that allows it to get pushed open by increasing water pressure?

_________________

"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings